192 Meckel's Cave Meningoencephaloceles Causing Typical Trigeminal Neuralgia

Abstract

INTRODUCTION: The culprit of trigeminal neuralgia (TGN) may occur on any point from the nerve’s root entry zone(REZ) to Meckel’s cave. Meckel’s cave meningoencephaloceles are rare middle cranial fossa defects that usually remain asymptomatic but may contain prolapsed trigeminal nerve rootlets and result in TGN. METHODS: A systematic review was conducted in accordance with the PRISMA guidelines for all reports of middle cranial fossa defects causing trigeminal nerve-related symptoms. The pathophysiology, presentation, surgical management and outcomes are illustrated with clinical case. RESULTS: Initial search from inception to March 2021 identified 33 articles for screening. After applying inclusion and exclusion criteria, 6 articles were included representing a total of 8 cases in addition to our case (n = 9). All 9 patients were females and 33.3% (n = 3) presented with classic trigeminal neuralgia. The preferred treatment modality was surgical with subtemporal extradural repairs using various combinations of autologous fat and muscle grafts and synthetic dura. Postoperative outcomes were only available in 55.5% (n = 5) of the cases and nearly all reported complete symptom resolution, except for one case in which the meningoencephalocele wall was incised, along with trigeminal rootlets adhered to it. Our patient had immediate and durable symptom relief after a 4-year follow-up. CONCLUSION: MEC containing prolapsed trigeminal fascicles can cause typical trigeminal neuralgia from chronic pulsatile stress. This supports the hypothesis that the compressive or demyelinating culprit can locate more ventrally on the course of the trigeminal nerve. Subtemporal extradural surgical repairs can be safe, effective and durable. Incising the MEC wall should be avoided as it may have trigeminal rootlets adhered to it.